The present invention relates to optical bar code scanners, and more particularly relates to a method for programming the operation of an optical bar code scanner.
The use of bar coded symbols or labels intended to be read by optical scanning equipment as a means for identifying data useful in processing items sold in the retail system has been widely accepted to the point that a particular bar code known as a Universal Product Code (UPC) has been established as the industry standard for the grocery and other related retail industries. In multiple bar code systems, such as UPC, each decimal number or character is represented by two pairs of vertical bars and spaces within a 7-bit pattern wherein a binary 1 bit represents a dark module or bar of a predetermined width and a binary zero represents a light module or space. Thus, the decimal or character 1 may be represented in the UPC code by the 7-bit pattern 0011001. In keeping with this format, the decimal 1 would be comprised of an initial space of a 2-bit width, followed by a 2-bit wide bar, another 2-bit space and a 1-bit wide bar.
A multiple bar code, such as the UPC, is normally read by an optical scanner which may take the form of a hand-held wand or a scanner mechanism located in a check-out counter. The optical scanner will scan the bar code patterns and generate signals representing the bars and spaces for transmission to the processing apparatus which determines the character represented by the bar code pattern.
In the manufacture of the bar code scanner, the scanner is initially programmed to read a tag, to send the coded data to a remote microprocessor, to operate the laser and also the motor which operates a portion of the scanning optics producing a scan pattern for scanning the coded label. One method of programming a scanner is found in U.S. Pat. No. 4,868,375 issued to D. Blanford and which is assigned to the assignee of the present invention discloses reading bar code labels for changing the program of the scanner. After the scanner has been installed in a checkout environment, conditions arise which require that certain functions of the scanner be changed. For example, the type of coded tag that is to be read might be changed requiring a different decoding system, the length of the tag may change and the communication interfaces together with the baud rate may be changed. Where these changes have occurred in the past, a service person was required to make such changes to the scanner.
It would be desirable to provide a method for altering the scanner functions which is simple and effective and does not require the services of a technician to make such changes.